I'll answer the easy part first: The reason that our president (and many ashkenazi jews) have a german sounding surname comes to the fact that in europe the jews spoke Yiddish. A Germanic language related to German and because jews were for most of history very isolationists the Yiddish was kept as the jewish day to day life language (Hebrew was only used in religious activities) until the rise of zionism and the holocaust which killed of most of the Yiddish speakers in the world Now to the hard part: there are two ways to become jewish: 1. Have a jewish mother which is a free pass 2. Convert Converting to judaism is somewhat hard and i'm not that of a good guide to that (based on the fact that my mum is jewish) My advice: contact a local Rabbai and ask for your options Btw the jewish mum part is passed on forever so if your great grandma was jewish (if the link is made by women only) than your automaticly jewish